Thorough scouting in 1912 has shown that no blight exists west of a
line drawn through central Somerset and Cambria counties, along the
extreme eastern border of Cameron County, to the northeast corner of
Tioga County. West of this line, nine isolated spot infections were
found in six counties, but all of these infections were eradicated as
soon as found, and have been under careful surveillance since. These
infected spots were located in Fayette, Elk, Warren, Potter, Clarion
and Indiana counties, and five out of the nine spots were found to be
due to the planting of diseased nursery stock purchased from nurseries
in the infected region. In April, 1913, the infection in Indiana County
was discovered in a shipment of three chestnut trees purchased from a
nursery in New Jersey. These examples show very strikingly the ease
with which the blight is widely distributed through the shipment of
nursery stock. Persons who have planted nursery grown chestnut trees in
regions free from the blight, should watch these trees carefully for
the first appearance of the disease, and promptly destroy all infected
trees.
Field work in the Western District during the period covered by
this report has been confined to Tioga, Clinton, Lycoming, Centre,
Huntingdon, Blair, Bedford, and Somerset counties. Tioga, Clinton,
Centre, and Blair counties have been scouted and most of the diseased
trees removed, but a considerable amount of infection still remains
in Lycoming, Huntingdon, Bedford, and Somerset counties. In addition,
Fulton and Mifflin counties still have a large amount of infection
remaining, since with the small field force it was impossible to
continue the work in these counties.
The accompanying map shows the progress of the control work in the
Western District, and the location of infected areas. The following
tabulation is a statement of the number of infected trees found and cut
out in the Western District from the time the work was begun until July
1st, 1913:
[Illustration:
Map showing spot infection in the western half of Pennsylvania to July
1, 1913, indicated by circles. Figures inside the circles indicate the
number of diseased trees found in each locality.
Inspection in eastern half of the State is generalized from the best
information available.]
STATEMENT OF CHESTNUT BLIGHT INFECTION IN THE
WESTERN DISTRICT.
==============+==================+==============+==============
County. | Number of tracts | Total number | Total number
| on which | of infected | of infected
| infection was | trees found. | trees removed.
| found. | |
--------------+------------------+--------------+--------------
Allegheny, | | |
Armstrong, | | |
Bedford, | 147 | 4,027 | 2,787
Bradford, | 91 | 1,048 | 829
Blair, | 225 | 1,884 | 1,680
Beaver, | | |
Butler, | | |
Cameron, | | |
Centre, | 142 | 2,556 | 1,763
Clinton, | 169 | 3,481 | 2,704
Clearfield, | 9 | 117 | 117
Clarion, | 1 | 1 | 1
Cambria, | 9 | 450 | 450
Crawford, | | |
Elk, | 6 | 377 | 377
Erie, | | |
Fayette, | 2 | 11 | 11
Fulton, | 90 | 1,902 | 900
Forest, | | |
Greene, | | |
Huntingdon, | 233 | 5,287 | 4,771
Indiana, | 1 | 1 | 1
Jefferson, | | |
Lycoming, | 259 | 5,015 | 4,486
Lawrence, | | |
Mifflin, | 95 | 1,976 | 1,468
McKean, | | |
Mercer, | | |
Potter, | 1 | 1 | 1
Somerset, | 92 | 9,110 | 8,093
Sullivan, | 22 | 207 | 207
Tioga, | 12 | 43 | 43
Venango, | | |
Westmoreland, | | |
Washington, | | |
Warren, | 3 | 16 | 16
+------------------+--------------+--------------
Total, | 1,609 | 37,510 | 30,705
--------------+------------------+--------------+--------------